Computing devices, such as notebook computers, personal digital assistants, mobile communication devices, portable entertainment devices (e.g., handheld video game devices, multimedia players), and set-top-boxes (e.g., digital cable boxes, digital video disc (DVD) players) may include user interface devices that facilitate interaction between a user and the computing device.
One type of user interface device that has become more common is a touch-sensor device or touch input device that operates by way of capacitance sensing. A touch-sensor device may be in the form of a touchscreen, touch-sensor pad, a touch-sensor slider, or touch-sensor buttons, and may include an array of one or more capacitive sensor elements. Capacitive sensing typically involves measuring a change in capacitance associated with the capacitive sensor elements to determine a presence or position of a conductive object relative to a touch input device. The conductive object may be, for example, a stylus or a user's finger. Measuring changes in capacitance may be challenging when signals indicating the change in capacitance are mixed with noise signals.